Util.Run - return an object from sub query?

timohayes · November 2018

Is there any way to return an object when using Util.Run?

I keep getting an error: Object of type 'System.Object[]' cannot be converted to type 'System.String[]
I've tried returning a dynamic, an object, and a string, but all fail with the same error.
My subQuery that is being called from another query with Util.Run has signature:
string Main(string[] args)

llewelyn · November 2018

I've managed to return.

First query saved to C:\PathToSubquery\Subquery.linq:


string Main(string input)
{
   return input;
}

Second query:


void Main()
{
   var queryExecutor = Util.Run("C:\\PathToSubquery\\Subquery.linq",QueryResultFormat.Text, "INPUT");
   ((string)queryExecutor.ReturnValue).Dump();
}

Dumps INPUT.

timohayes · April 2019

Returning to this, I still can't successfully return an object. My sub-query signature looks like this:
async Task<SomeObject> Main()
and returns an object (class is defined in My Extensions).

My second query calls the sub-query like this:

var qryRunner = Util.Run("MySubQuery.linq", QueryResultFormat.Text, null);
SomeObject result = qryRunner.ReturnValue;

The return value is always null.

jamesmanning · May 2019

@timohayes AFAIK in order for linqpad to be able to return the object through Util.Run like that, it needs to be marked serializable. I was able to reproduce the behavior you're seeing when it didn't have [Serializable], and once I added that attribute it worked fine.

@JoeAlbahari is this true? If it is, could there be a warning added when Main returns a non-void/non-serializable type? Presumably Main doing so is specifically so other scripts could call it and would hit this issue AFAICT

JoeAlbahari · May 2019

Yes, I'm looking into making some upgrades to this in LINQPad 6.

Making the type serializable will work only if the type is visible to both scripts (defined in My Extensions or a common assembly).

Util.Run - return an object from sub query?

Comments